Field of the Invention
The present invention relates to an image pickup apparatus and a capsule endoscope.
Description of the Related Art
As an optical system having a wide angle of view, which forms a curved image, a zoom lens and an image pickup apparatus have been proposed in International Unexamined Patent Application Publication No. 2013/027516. In this image pickup apparatus, by using an image pickup element having a light-receiving surface (an image pickup surface) of which a spherical concave surface is directed toward an object side, Petzval's sum is in acceptable range, and a degree of freedom of selecting a glass material is improved.